Professor Simon Benjamin
Department of Materials
Tel: +44 1865 273777 (reception)
Fax: +44 1865 273789 (general fax)
1. New technologies that explaoit quantum physics: quantum sensors, quantum communications, and quantum computing. Theory to support the developement of these technologies on various platforms, including novel silicon and diamond based materials.
2. Energy harvesting, transfer and storage understood at the quantum level. Modelling of energy flow phenomena in both artificial and living (e.g. photosynthetic) systems.
Coherent Control of Spin Systems
Dr. S.C. Benjamin, Dr. B.W. Lovett*, Dr. E.M. Gauger
We are studying the quantum properties of nuclear and electron spins, primarily in molecular systems. Our aim is to provide theory that will allow for the control small numbers of spins, such that the quantum coherence is preserved for as long as possible. We collaborate with the Quantum Spin Dynamics experimental group in London (http://www.ucl.ac.uk/qsd), and together we demonstrated that the quantum state of an electron spin can be transferred coherently to a nuclear spin, thus increasing the coherence time. We are now working on optical methods for further improving coherence, and for coupling several spins together. (*Heriot-Watt University)
Architectures and materials for robust and scalable quantum technologies
Dr. S.C. Benjamin, Ms Naomi Nickerson
Today's computers may seem very powerful, but their designs do not take advantange of the enormous potential power of quantum physics. We know that it is possible, in principle, to build an entirely new class of technology that would harness effects like quantum superposition and quantum entanglement in order to profoundly outperform all conventional machines (at least for certain key tasks). However such technologies are very challenging to build in reality. It particular it is difficult to take the small prototype systems in the laboratory and scale them up to the point that they start to exceed the capacities of conventional technologies. This project is about finding ways to build these technologies that are robust, in the sense that they can operate with realisitic levels of imperfection, and also scalable -- so that once you have a few components working together, it is straightforward to add more and more. For example: One approach would be to build the large machine by networking together many simple processor cells, thus avoiding the need to create a single complex structure. See for example our open Nature Communications paper: http://www.nature.com/ncomms/journal/v4/n4/full/ncomms2773.html
Quantum energy calculations for artificial and biological nanostructures
Dr. S.C. Benjamin, Dr. B.W. Lovett*, Dr. E.M. Gauger, Mr Higgins, Mr Pollock
In order to best understand how to engineer molecular scale systems that can harvest, transfer and store energy, it is necessary to understand energy transfer at the quantum level. There is evidence to suggest that Nature's molecular technologies, for example the structures involved in photosynthesis, perform energy transfer in a way that involves quantum coherence. This is a surprise since quantum effects are usually thought to be difficult to achieve and more the province of the physics laboratory than a "warm and wet" biological system. We are developing new analytic and numerical techniques to understand energy transfer as a fully quantum mechanical process, and aiming to apply this both to natural systems and to artificial structures created by our experimental collaborators. The task is challenging, but the answers may eventually allow us to design highly efficient molecular scale technologies.(*Heriot-Watt University)
Quantum superposition in large systems
Dr. S.C. Benjamin, E. Gauger, Professor G.A.D. Briggs, G. Knee
This is a theoretical project looking at the possibilities inherent in creating quantum superpositions of large objects such as massive molecules or SQUIDs and similar. A key theoretical tool is be the Leggett-Garg inequality, which tests to see if a system needs quantum physics to describe its behavoir. We are now buildings on the early success of this project, which we reported in this open Nature Communications paper: http://www.nature.com/ncomms/journal/v3/n1/full/ncomms1614.html
4 public active projects
Nickerson, N., Li, Y. and Benjamin, S. C., 'Topological quantum computing with a very noisy network and local error rates approaching one percent' Nature Communications 4, Article 1756 (2013) OPEN article http://www.nature.com/ncomms/journal/v4/n4/full/ncomms2773.html
Li, Y., Barrett, S., Stace, T. and Benjamin, S. 'Long range failure-tolerant entanglement distribution' New J. Phys. 15 023012 (2013)
Knee, G. C., Briggs, G. A. D., Benjamin, S. C. and Gauger, E. M., 'Quantum sensors based on weak-value amplification cannot overcome decoherence, Phys. Rev. A 87, 012115 (2013)
Ping, Y., Lovett, B. W., Benjamin, S. C. and Gauger, E. M., Practicality of spin chain 'wiring' in diamond quantum technologies, Phys. Rev. Lett. 110, 100503 (2013)
Ping, Y., Gauger, E. M., and Benjamin, S. C. 'Measurement-based quantum computing with a spin ensemble coupled to a stripline cavity' New J. Phys. 14, 013030 (2012)
Knee, G. et al, 'Violation of a Leggett–Garg inequality with ideal non-invasive measurements' Nature Communications 3, Article number: 606 (2012) OPEN article http://www.nature.com/ncomms/journal/v3/n1/full/ncomms1614.html
*Architectures and algorithms for near-future quantum machine learning and optimization
Prof S C Benjamin
This is a theory project to be hosted in Prof. Simon Benjamin’s Quantum and Nanotechnology Theory Group (see qunat.org).
Background: At present in the UK and worldwide there is a major drive towards developing quantum technologies. These are devices that harness the deeper principles of quantum physics in order to outperform conventional technologies. The most challenging and perhaps the most important goal of this field is to create quantum computers — machines that store and process qubits (quantum bits) rather than bits.
Oxford is leading one of four UK “Quantum Hubs”. Each Hub is an alliance of universities that are working to accelerate progress towards a particular kind of quantum technology; the Oxford-led Hub is called “Networked Quantum Information Technologies” and is focused mainly on creating quantum computers (see NQIT.org).
Studentship details: This studentship is concerned with finding new applications for quantum computers. The two main areas of investigation will be machine learning and optimisation. Machine learning is a very active field of research for conventional computer science, with applications in areas ranging from big data analysis through to medicine and self-driving cars. The aim of this project will be to seek for opportunities to use quantum systems to accelerate important tasks in machine learning, including for example the training of neural networks. Meanwhile ‘optimisation’ refers to finding the best solution to a complex problem with many variables — a practical example might be routing supply vehicles for a large courier company. Solving optimisation problems is very important commercially, and it has been suggested that early quantum technologies (including the machines that are already sold by the company D-Wave) may be able to perform optimisation more efficiently than conventional computers. This will be explored with analytic theory, numerical simulations, and (very probably) by directly using D-Wave hardware which the QuNaT group has access to.
This project would suit a student with a strong physics, mathematics or computer science background. Prior experience in machine learning or optimisation is not required but an enthusiasm to learn is essential! Oxford has a very large machine learning community and offers many courses etc.
Candidates are considered in the January 2017 admissions cycle which has an application deadline of 20 January 2017.
The NQIT Hub is funded by an award to a consortium of nine universities and is supported by a number of commercial and governmental partners, including the EPSRC. This 3-year studentship will provide full fees and maintenance for a student as home fee status (this includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study). The stipend will be £14,296 per year. Other EU students should read the guidance at http://www.materials.ox.ac.uk/admissions/postgraduate/eu.html for further information about eligibility.
Any questions concerning the project can be addressed to Professor Simon Benjamin (email@example.com). General enquiries on how to apply can be made by e mail to firstname.lastname@example.org. You must complete the standard Oxford University Application for Graduate Studies. Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.
Also see homepages: Simon Benjamin
Also see a full listing of New projects available within the Department of Materials.